1. Technical Field
The present invention relates to CMOS (Complementary Metal Oxide Semiconductor) sensors, and more specifically, to the CMOS sensors that have charge pushing regions.
2. Related Art
A typical CMOS sensor comprises a photo diode and a transfer gate. After light is shined on the photo diode, free electrons are created in the photo diode. Then, those free electrons are transferred to a floating diffusion region through the transfer gate. It is desirable to transfer as many free electrons as possible to the floating diffusion region through the transfer gate. Therefore, there is a need for a structure and method to help transfer as many free electrons as possible from the photo diode to the floating diffusion region through the transfer gate.